Interchangeable stylus mechanism for pickups



p 21, 1965 KENKICHI TSUKAMOTO 3,207,519

INTERCHANGEABLE STYLUS MECHANISM FOR PICKUPS Filed May 14 1963 SAT N a, @uIlllIlll United States Patent 3,207,519 INTERCHANGEABLE STYLUS MECHANISM FOR PICKUPS Kenkichi Tsukamoto, 47 Koyamashimofusa-cho, Kita-ku, Kyoto-shi, Japan Filed May 14, 1963, Ser. No. 280,340 Claims priority, application Japan, May 16, 1962, 37/ 19,941 1 Claim. (Cl. 274-36) This invention relates to phonographic pickups, and more particularly it relates to a new and improved interchangeable stylus mechanism for pickups.

An interchangeable stylus mechanism wherein replacement of the stylus can be accomplished in a simple manner without the use of a screwdriver or a special tool, and which is such that absolutely no play or looseness develops therein is desirable but, heretofore, has not been attained. Among the various known kinds of inter changeable stylus mechanisms for pickup cartridges, there have been those, such as the so-called type, wherein one end of a vibrator protruding outwardly from a pickup cartridge is engaged with a cantilever having a stylus secured to one end thereof, the assembly so engaged functioning to transmit vibration. In this type, however, the interchangeable stylus mechanism has hitherto been secured in place by a screw means or simply by a spring means which readily gives rise to play or looseness.

In view of the foregoing consideration, it is an object of the present invention to provide an interchangeable stylus mechanism which can be removed and replaced in a simple and positive manner by means of only a finger tip, without the necessity of any special tool whatsoever, and in which there is no possibility of play or looseness developing, and, moreover, a cantilever is protected by a trough-shaped box. This object has been attained, in a simple manner through the utilization of the principle of the wedge and a spring.

The nature, principle, and details of the invention will be more clearly apparent by reference to the following detailed description of a preferred embodiment of the invention when taken in conjunction with the accompanying drawing in which like parts are designated by like reference numerals, and in which:

FIGURE 1 is a side elevational view, in vertical section, showing the embodiment of the interchangeable stylus mechanism according to the invention;

FIGURE 2 is a bottom plan view of the embodiment shown in FIGURE 1; and

FIGURE 3 is a front-end elevational view of a spring suitable for use in the mechanism of FIGURES 1 and 2.

Referring to the drawing, an essential part of the mechanism of the present invention is a trough-shaped box 7 having a cross section of semicircular or channel shape and a rear end shaped in the form of a wedge 5. The cartridge 1 (shown only as a fragment thereof) of the pickup is provided at its lower front end with a groove 8, in which the box 7 fits snugly, with a tapered rear end to mate with the wedge 5 and is provided at its front end with a spring 6 adapted to snap onto the Patented Sept. 21, 1965 front end of the box 7 and press the box 7 toward the rear. Thus, in fitting the box 7 into the groove 8, the box 7 is inserted so that its rear-end wedge 5 catches in the said tapered rear end of the groove 8 and is pushed upwardly until its front end is caught and held by the spring 6, whereby the rearward force exerted thereon causes the wedge 5 to be forced into the mating tapered end of the groove 8 and thereby to be firmly and rigidly locked in place relative to the cartridge 1.

The box 7 protectively contains and supports a cantilever 4 provided at its front end with a stylus 3 and has an opening 9 in its uper part through which the lower end of a vibrator 2 extending outwardly from the cartridge 1 engages with the cantilever 4 when the mechanism is in the assembled state.

The front surface of the spring 6 may be advantageously utilized by inscribing thereon a trademark or a decorative figure.

According to the stylus replacement mechanism of this invention, it has become possible at the first time in the world to realize mass production of a moving coil type pickup of stylus replacement type which has not yet been realized in spite of its requirement because its manufacture has been deemed to be impossible. Accordingly, the present invention has an excellent effect.

Although this invention has been described with respect to a particular embodiment thereof, it is not to be so limited as changes and modifications can be made therein which are within the full intended scope of the invention, as defined by the appended claim.

What is claimed is:

A stylus replacement box mechanism for phonographic pickups comprising a box of inverted trough shape protectively containing and supporting a cantilever which is provided at one end thereof with a firmly secured stylus, said box having a wedge-shaped rear end, and an opening at its upper part, a groove formed at the lower front end of a pickup cartridge so as to snugly receive the said box and provided at its rear with a tapered end to mate with the said wedge-shaped rear end of the said box, and a spring provided at the front end of the pickup cartridge and adapted to snap onto the front end of the said box and to force the said box rearwardly so as to establish tight mating between the said wedge-shaped rear end of the said box and the said tapered end of the said groove, whereby the said box is locked tightly and rigidly in place relatively to the pickup cartridge, the said opening at the upper part of the said box being so positioned as to permit the outer end of a vibrator extending outwardly from the pickup cartridge for the purpose of receiving vibrations to extend therethrough and engage with the said cantilever.

References Cited by the Examiner FOREIGN PATENTS 801,361 9/58 Great Britain.

NORTON ANSHER, Primary Examiner. 

